Breech bolt carrier assembly and slide cover therefor



Feb. 13, 1968 B. w. BROWNING 3,368,298

BREECH BOLT CARRIER ASSEMBLY AND SLIDE COVER THEREFOR Filed Jan. 5, 1967 2 Sheets-Sheet l FIG. I.

FIG.3

INVENTOR.

BRUCE W BROWNING H l S ATTORNEY Feb. 13, 1968 B. w. BROWNING 3,368,298

BREECH. BOLT CARRIER ASSEMBLY AND SLIDE COVER THEREFOR Filed Jan. 5, 1967 2 Sheets-Sheet 2 efi 66 I2 2| Q as Ill/Ill a, 67

FIG.5

INVENTOR. BRUCE W BROWNING HIS ATTORNEY United States Patent T 3,368,298 BREEH BUIJI" CARRIER ASSEMBLY AND SLIDE CUVER THERIJEUR Bruce W. Browning, @gden, Utah, assignor to Browning Industries, incorporated, Morgan, Utah, a corporation of Utah Filed Ian. 3, I967, Ser. No. 506,846 8 (Iiaims. (CI. 42-16) ABSTRACT OF THE DISCLQSURE This invention provides an improved breech bolt carrier assembly incorporating a novel, telescoping slide cover for permitting proper breech closure and opening while reducing bolt and receiver size and related structure of the firearm.

The present invention relates to breech bolt assemblies reciprocating in the receivers of firearms and, more particularly, to a new and improved, breech bolt assembly and telescoping slide cover combination offering a number of distinct advantages as to receiver closure and also extractor installation and operation, as shall be enumerated hereinafter.

Considering a first aspect of the invention, an improved extractor and extractor-spring combination is provided the breech bolt of the breech bolt carrier assembly. This is accomplished in such manner that the extractor spring and extractor are extremely conveniently assembled to the head of the breech bolt of the structure. This is performed in such a manner that the extractor is adapted for radial, translational displacement movement relative to the head of the breech bolt, and is resiliently retained for such movement from its nominal position by the end of the extractor spring. The extractor spring, itself, is so disposed that once the end of the extractor spring is caused to engage the extractor, then the annular portion thereof may be easily snapped into a peripheral groove about the breech bolt. This composite structure obviates the difliculties of installation present in conventional breech bolt structures.

A second aspect of the invention concerns itself with the problem of reduction in size and cost of the receiver and breech bolt assembly of the firearm. Heretofore, the breech bolt carrier assembly has had to be unusually long in size, this to provide complete closure of the ejection opening of the receiver when the bolt is locked for firing. The ejection opening, of course, is necessarily long so as to accommodate ejection of spent cartridges. If the breech bolt carrier assembly is shortened over that which is usually the case, then the interior of the receiver is exposed, through the shell ejection opening, to the outside, thus chancing the entrance into the receiver of foreign objects of dust and dirt which might tend to foul the mechanism. In the present invention there is provided a novel telescopic slide which is actuated by the slide carrier and which is designed to completely close the shell ejection opening of the receiver at all times when the same is desired. Slidable telescoping engaging of the slide cover may be accomplished either through keyed contact thereof either with the carrier of the bolt carrier assembly or with the receiver itself.

Accordingly, a principal object of the present invention is to provide a new and improved bolt carrier as sembly for firearms.

A further object of the invention is to provide in a 3,368,293 Patented Feb. 13, 1968 breech bolt of a bolt carrier assembly an improved extractor and extractor spring combination.

An additional object is to provide in a breech bolt an extractor and extractor spring combination which is easily mounted to the structure and which facilitates springbiased radial displacements of the extractor, relative to the center of the bolt head, in a manner to be desired.

An additional object is to provide with a bolt carrier assembly an improvement comprising the addition of a novel, telescopic slide cover to aid selectively in closing the shell ejection opening of the receiver of the firearm.

A further object is to provide in a firearm an improved bolt carrier assembly which co-acts with a telescoping slide cover, keyed either to the receiver or to the carrier of the assembly, so that when the breech bolt is approaching or at its foremost position, the telescoping slide may close, either substantially or completely, the receiver opening provided for shell ejection.

An additional object is to provide in a firearm a breech bolt carrier assembly such that the bolt, slide carrier and receiver may be made as short as possible, this through utilization of a telescopic slide cover to assist, at least, in closing the ejection opening of the receiver of the firearm at desired times.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings in which:

FIGURE 1 is an exploded view of a breech bolt carrier assembly alone, the breech bolt incorporating the extractor principles and structure contemplated by the present invention.

FIGURE 2 is a front elevation of the head of the breech bolt and is rotated clockwise direction for convenience of illustration.

FIGURE 3 is a fragmentary section taken along the line 3-3 of FIGURE 2.

FIGURE 4 is a plan view of the breech bolt carrier assembly minus the telescopic slide cover.

FIGURE 5 is a longitudinal vertical section taken along the line 55 in FIGURE 4.

FIGURE 6 is an end view of the structure shown in FIGURE 5, including the telescoping slide cover keyed to the carrier thereof, and is taken along the line 66 in FIGURE 5.

FIGURE 7 is an elevation, similar to FIGURE 5, but illustrates the inclusion of the telescopic slide cover at its position when the same is engaged and thereby positioned forwardly by the carrier of the breech bolt carrier assembly when the latter is locked home.

FIGURE 8 is a view similar to FIGURE 7 but illustrates the telescopic slide cover when drawn rearwardly through the retrieval of the breech bolt carrier assembly.

In FIGURE 1 the breech bolt carrier assembly 10 is shown in exploded view and includes as its principal members a slide carrier 11 and a breech bolt 12. Breech bolt 12 is fitted into the slide carrier 11 such that the rearward extremity 13 of breech bolt 12 is slidably received by bore 14 of the slide carrier 11. Conventional timing latch 15, forming no part of the present invention, is fitted into a slot (not shown) of slide carrier 11, and timing latch pin 16 pivotally secures the timing latch at its bore 17 to relief area and bore 18 of the slide carrier 11.

The breech bolt 12 includes a conventional camming aperture 19, a cam pin is pressed into the slide carrier 11, at aligned apertures 21, and passes through the camming aperture 19 of the breach bolt. This provision for camming the breech bolt for rotation within the locking lugs of the receiver, via lugs 22, 23, and 24 of the breech bolt, is strictly conventional, Likewise conventional is the provision of a firing pin 25 which is provided with compression spring 26, these two parts being inserted through bore 27 of the breech bolt and bore 28 of the cam pin 20 aligned therewith. A firing retainer pin 29 is inserted in .aperture 30 of the breech bolt and cooperates with pin-receiving stop recess 31 of firing pin 25.

For ease of assembly there may be provided an undercut groove accommodates the reception of outwardly extending guide rails 33 of operating handle 34. In operating handle 34 latch 35 includes an inwardly-directed detent 36 cooperating with bore 37 of slide carrier 11. A spring 38 may be disposed between the operating handle latch 35 and the operating handle 34. A latch pin 39 is disposed through cooperating apertures 40 and 41 of the indicated parts to secure the latch 35 to the operating handle 34 in a pivotal manner. Hence, the easy release of the operating handle and latch may be accomplished by the user simply taking a small screw driver and lifting outwardly upon operating handle latch 35 underneath the lip 42 thereof.

An ejector 43 includes a limit slot or aperture 44, the latter receiving ejector pin 45. Ejector pin 45 is pressed into an aperture 46 of the breech bolt to so retain the ejector 43. A compression spring 47 is conventionally supplied to the cooperating shoulder bore, not shown, in the breech bolt, this to supply spring compression against ejector 43 of the conventional manner. This particular portion of the structure is strictly conventional.

So far as the breech bolt is concerned, an important part of the present invention centers in the provision of an extractor 50 and extractor spring 51 combination, and in particular, in their mutual configuration and cooperation. Extractor 50 includes outwardly-extending guide portions 52 which cooperate with undercut grooves 53 of radial undercut groove means 54 provided in the head 55 of breech bolt 12. Of course, as to the extractor 50 and breech bolt, either may be undercut relative to the other, or some other provision may be made so that the extractor is secured to outwardly slidably displaceable with respect to the breech bolt. In the embodiment shown, radial undercut groove means receives the extractor such that the extractor may move in radial fashion. It is noted that the extractor may include an inwardly-directed tooth 57 for releasably locking the end of a cartridge within the firing chamber of firearm. Co-acting with the extractor is the extractor spring 51 having an annular portion 58 and an elongate portion 59. Correspondingly, the breech bolt 12 is provided with an annular groove 60, also an elongate longitudinally-oriented groove 63 and bore passageway 64, which is preferably oversize as to cross-section to accommodate selective operative displacement of spring portion 59. Passageway 64 communicates with the aperture 65 of the extractor spring 51. FIGURE 3 illustrates this portion of the assembly wherein the extractor spring 51 (see FIGURE 3) is seated in groove 60 such that the elongate portion 59 of the spring proceeds along seat 63 and through aperture 64 to communicate with and engage aperture 65 of extractor 50. This is an extremely simple, straight-forward way of spring-connecting the ejector within the head of the breech bolt. By such a connection and through the resiliency of the spring (tending to retain the elongate portion 59 of the spring in its straightened condition) the extractor is able to move easily up and down radially with respect to undercut groove means 54 of annular rim 12 in the head of breech bolt 12. The spring constant of the springs 51 and 47 will be chosen such that when the breech bolt is withdrawn, the spring cut groove 32 in'the'sid'e o'f'sl'ideca'rrie'r 11, which under tension supplied to ejector 43 will be sufficient to eject out of the receiver a spent shell, so that the end flange of the shell is released from tooth 57 of extractor 50.

FIGURE 2 illustrates the position of extractor 50 in the head of breech bolt 12 and the fact that the same is easily radially displaced within undercut groove means 54 of the breech bolt head. It is noted that the extractor is easily placed and secured to the spring by the operator first thrusting the elongate portion 59 of spring 51 through aperture 64 and within longitudinally oriented groove 63, and thereafter rotating the spring about the axis of elongate portion 59 until the looped or annular portion 58 snaps around the breech bolt to engage groove 60.

The cooperation of timinglatch 15 with the breech bolt, in selectively fixing the disposition of the same relative to the slide carrier 11 during a selected time of the operating cycle, is strictly conventional and forms no part of the present invention. This is also true in connection with the actuation of the firing pin 25 and the function and operation of the ejector 43. Likewise, the camming of the bolt to lock the same within the lugs (not shown) of the receiver is strictly conventional.

FIGURE 4 is a plan view of the assembled breech bolt carrier assembly shown in exploded view in FIGURE 1. In FIGURE 4, however, the slide carrier 11 includes an upstanding protuberance 66, and elevation of the assembled breech bolt carrier assembly is shown in FIGURE 5 wherein it is seen that the protuberance 66 is upstanding from the main portion of slide carrier 11 (corresponding to slide carrier 11 in FIGURE 1).

FIGURE 5 illustrates the combined assembly except for the telescoping slide which will be described hereinafter. It is noted that a shell seat 67 is formed in the head of breech bolt 12. The firing pin 25 extends through the structure such that the tip 68 thereof is in proximity with seat 67. Accordingly, the impact of the hammer upon firing pin 25 causes a firing of the cartridge in the usual manner. S represents a camming surface by which the reciprocating breech bolt carrier assembly may cam the hammer down to cocking position. See in this and other regards the inventors copending United States patent applications entitled Firearm Assembly, Ser. No. 606,844, filed Jan. 3, 1967, and Firearm Improvement, Ser. No. 606,845, filed Jan. 3, 1967, which are fully incorporated herein by way of reference.

The telescoping slide cover, about to be discussed, will be understood to be part of the bolt carrier assembly when the same is keyed to the carrier for slidable movement with respect thereto, but merely cooperates with the bolt carrier assembly through engagement therewith when the telescoping slide cover is keyed for slidable movement to the receiver of the firearm.

FIGURE 6 illustrates one way in which a telescoping slide cover 69, incorporating the features of the present invention, may be keyed to the breech bolt carrier assembly. It Will be seen that the telescoping slide cover 69 includes an inwardly-directed flange or key 70 fitting into slot 71 which is grooved longitudinally into the outer side of slide carrier 11. The slide cover may be made resilient relative to its transverse direction and its contour may be chosen so as to traverse greater than of are relative to the periphery of the slide carrier 11. In this manner the telescoping slide cover may be easily keyed via groove 71 for free, telescoping, slidable movement over slide carrier 11. The slidable movement of the telescoping slide cover 69 should be free with respect to the remainder of the structure excepting that there may be provided a friction dimple 72 which, upon contact with the slide carrier, will retard the forward progress of the telescoping slide cover 69 with respect to slide carrier 11.

In FIGURE 7 the direction of movement of the assembly is terminated to the right, as shown by the arrow A, to close and lock the bolt home for firing. During such forward movement the protuberance 66 will engage the right-hand edge 73 of slot 74 of the telescoping slide cover 69. In addition to the protuberance 66, or in substitution thereof, the forward lip 75 of slide cover 69 may be turned down so as to serve as a carrying abutment for slide carrier 11 (11'). In the condition shown in FIGURE 7, it is seen that the carrier assembly actually pulls along, as before explained, the telescoping slide carrier 69.

Relative to FIGURE 7, the assembly and slide cover have closed home for firing. Receiver 76 includes the usual shell ejection opening or aperture 77 and also a slot 78 communicating therewith which serves with a relief slot to accommodate reciprocation of operating handle 34 in FIGURE 1. It is noted in FIGURE 7 that the breech bolt and carrier are of reduced dimensions lengthwise. This is made possible through the provision of the elongate slide cover which serves to keep the ejection opening 77 covered, even though the breech bolt is guided all the way home and locked into firing position.

After firing, as shown in FIGURE 8, the assembly will move in the direction B. In such an event, and depending upon construction, either the rearward lip 79 of telescoping slide cover 69, or the edge 80 of slot 74, or both will coact with the rear edge 81 (and/or rear edge of protuberance 66) so that the telescoping slide cover 69 will be withdrawn to the left relative to slide carrier 11 (11). To prevent a loose fitting of the parts during their extreme rearward travel, friction detent 72 may be provided and be caused to engage the side surface of slide carrier 11. This action serves to slow down the relative travel to the right of the telescoping slide cover in relation to slide carrier 11 (II'), and hence prevents a rattling of the parts during their sequence of operation.

It is thus seen that slot 74 serves, in effect, as a lost motion connection between the protuberance 66, if used, and the slide cover. Again, protuberance 66 may be entirely removed and the forward and rear down-turned tabs 75 and 79 relied upon to produce the engagement with the breech bolt carrier assembly as heretofore described.

In summary of operation, the forward momentum to the right in the direction A in FIGURE 7 of the breech bolt and slide carrier serve to carry forwardly the slide cover. However, the slide cover is rearwardly displaced relative to the slide carrier so that that portion of the shell ejection opening rearwardly of the bolt will be covered by the telescoping slide. This is to be much desired when the bolt is locked home for firing and where that portion of the receiver which is to the rear of the bolt and slide cover would be uncovered, but for the inclusion of the telescoping slide 69.

It is noted that a retrieval or movement in the direction B or the bolt carrier assembly also accomplishes a rearward retrieval of the slide cover, but only after a lost motion time interval has elapsed so as to cause the slide carrier to advance to the rear, relative to the telescoping slide cover. This accommodates a shortening of the length of the receiver and its interior in order to accommodate the slide cover (and also the bolt carrier assembly).

It follows that the telescoping slide cover can be slidably keyed either to the slide carrier 11, or simply to the receiver proper as is indicated in FIGURE 4. The essential feature in this portion of the invention is for the slide cover to be actuated back and forth in accordance with the movement of the bolt and carrier combination, but with there being supplied a suflicient lost motion coaction between the slide carrier and the telescoping slide cover 69 so that the forward translation of the bolt and carrier will produce a rearward extension of the slide cover behind the bolt, this to cover the ejection opening of the shell, whereas a rearward retrieval of the breech bolt and carrier will cause a corresponding rearward movement of the telescoping slide cover to the rear so as to expose the ejection opening of the receiver, but only after the lost-motion coaction has taken place such that the telescoping slide cover is horizontally displaced to the right relative to the rearwardly-traveling bolt 12 and slide carrier 11 (11). A slot pattern 82, of course, will be supplied in telescoping slide cover so as to accommodate the travel of operating handle 34 in FIGURE 1.

As to this second aspect of the invention as above described, it is seen that even though long cartridges are used by the firearm in question and a relatively lengthy ejection opening is necessitated for accommodating shell ejection, yet the size of the receiver and the breech bolt and the slide carrier of the breech bolt carrier assembly (now not required to close the ejection opening) may be reduced substantially in length. This greatly reduces cost, both as to the bolt carrier combination and also the receiver, due to its shortened character; this all made possible solely because of the inclusion of a telescoping slide cover having its lost motion conection with the bolt carrier assembly. Thus, and in summary, the gun becomes more compact, the receiver is foreshortened, and the operating bolt and slide carrier are much reduced in dimension relative to corresponding structures in present firearms. This reduces the over-all cost and weight of the firearm and makes the same more convenient to handle.

While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

I. In a firearm having a receiver provided with a shell ejection opening and a bolt carrier assembly operatively disposed within said receiver; an improvement comprising a telescoping slide cover disposed over said bolt carrier assembly, said telescoping slide cover being keyed for slidable movement to one of said receiver and said bolt carrier assembly, said telescoping slide cover including means, constructed for alternate abutment by said bolt carrier assembly, for enabling said bolt carrier assembly to carry said telescoping slide cover in a direction the same as the then-current travel of said bolt carrier assembly, said enabling means being mutually spaced apart a suficient distance such that said bolt carrier assembly must travel a lost-motion distance from its abutment position with respect to one of said enabling means to its abutment position with respect to the remaining one of said enabling means, and said telescoping slide cover extending rearwardly of said bolt carrier assembly when the latter is in its forward position within said receiver.

2. Structure of claim 1 wherein said bolt carrier assembly includes a slide carrier slidably disposed within said receiver and a breech bolt operatively disposed within said slide carrier, said telescoping slide cover being keyed to said slide carrier in the manner aforesaid.

3. The structure of claim 1 wherein said telescoping slide cover is disposed between said receiver and said bolt carrier assembly.

4. The structure of claim 1 wherein said enabling means comprise depending tabs alternately engageable with said bolt carrier assembly.

5. The structure of claim 1 wherein said bolt carrier assembly includes a slide carrier and a breech bolt operatively disposed within said slide carrier, said enabling means comprising depending tabs alternately engageable with said slide carrier.

6. The structure of claim 1 wherein said bolt carrier assembly includes a slide carrier slidably disposed within said receiver and a breech bolt operatively disposed within said slide carrier, said enabling means alternately abutting said slide carrier of said bolt carrier assembly as aforesaid.

7. The structure of claim 1 wherein said telescoping 7 8 slide cover includes inwardly-directed friction means References Cited selectively engaging said bolt carrier assembly. UNITED STATES PATENTS 8. The structure of claim 7 wherein said bolt carrier assembly includes a slide carrier slidably disposed within 1 Ross 42-16 said receiver and a breech bolt operatively disposed With- 5 j i g A Q1932 in said slide carrier, said inwardly-directed friction means selectively engaging said slide carrier of said bolt carrier BENJAMIN A. BORCHELT, Primary Examiner. assembly as aforesaid. 

